Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_2589_Библиотеки_им_академика_М_И_Перельмана

It should be noted that the RNFs are non­medullated till they exit from the eye. Rarely, the RNFs may become medullated as an anomalous developmental process. These medullated RNFs are opaque and have a broad spectrum of clinical presentation both in extent and severity. Many times, even to the experienced observer, these may be mistaken for the CWS.However, unlike the CWS, the medullated bres are highly linear, have sharply dened borders and tend to obscure even the large retinal vessels near the optic disc (Figs.3.6 and 3.7) (Box 3.1).

retinal arterioles contract resulting in the occlu-

sion of the terminal arterioles.

insult to the RNFs. Depending upon the severity of hypoxia, there is either an infarction of the

3.2, and 3.8). CWS arise because of retinal

a reversible swelling of the RNF if the blood sup-

which is responsible for the intracellular swelling

nal arterioles non-compliant to any future sudden

rise in intravascular pressure. Thus, CWS are extremely unlikely in patients with essential hypertension (Boxes 3.2 and 3.3).

DBP≤85mmHg

permission of the publishers Elsevier

CWS, when seen in patients with diabetes melli­tus, indicate an abrupt worsening of diabetic reti­nopathy (Fig. 3.9). Interestingly, uncontrolled type 2 diabetics, when switched to insulin ther­apy for better control of blood sugar levels, may

Interestingly, on optical coherence tomogra­phy (OCT), the CWSs in the macular area show hyperreectivity in the RNF layer with corre­sponding non-perfusion on optical coherence tomography angiography (OCTA). On the other hand, the extramacular white spots show hyper­reectivity spanning from the retinal nerve bre layer (RNFL) to the outer plexiform layer with a corresponding ow decit on OCTA (Fig.3.11) [11]. It has been proposed that in the macular area, the deep capillary plexus (DCP) is seamless and gets its supply from overlapping arterioles and perfusion is not easily compromised com­pared to the extramacular white spots, which do not have such an arrangement and depend on oxygenation to the choroidal supply [12]. While the macular white spots generally do not expand, the extramacular spots tend to spread toward the optic disc. The non-perfused areas involve both the supercial capillary plexus (SCP) and DCP and the CWS are central to these and mark the junction of non-perfused and perfused areas and are considered a sentinel lesion. The CWS show marked thickening of the RNFL on SD-OCT, impinging on the rest of the retinal layers. Unlike the peripheral non-perfused areas that, on OCTA, show no ow in the SCP and DCP, the area of macular CWS shows a strong decorrelation sig­nal (Figs.3.11 and 3.12) [13]. CWS on resolution leave behind thinning of the inner retinal layers,

especially in the younger age group, decreasing estimated glomerular ltration rates, increasing serum creatinine, and higher HbA1c. Focal areas of retinal thinning have been proposed as a sur­rogate biomarker for systemic disease [14].

In an elderly asymptomatic patient, the pres­ence of CWS should alert the physicians to the possibility of GCA as a timely institution of high­dose corticosteroids can save the patient from blindness [17–20].

The American College of Rheumatology and the European Alliance of Associations for Rheumatology (EULAR) 2022 gave new classi­cation criteria for diagnosing GCA, the common­est cause of arteritic-AION.The essential criteria were age above 50 and ruling out other causes of medium or large vessel disease. They included a set of symptoms and signs, including morning stiffness in shoulders and neck, sudden onset of visual loss, jaw or tongue claudication, new tem­poral headache, scalp tenderness, cord-like thickening of the temporal artery, tenderness, and decreased or absent pulsations. Each of these was assigned a score of two. These were combined with information from a set of tests, including

ESR>50mm/rst hour or CRP>10mg/L, halo sign on ultrasonography of the temporal artery, a positive temporal artery biopsy, bilateral axillary artery halo sign, stenosis on angiography, or increased FDG uptake on PET CT scan. All crite­ria were given a score of two except a positive temporal artery biopsy, which was given a score of ve, and loss of vision and ESR/CRP were allowed scores of three each. A score of >6 gave a diagnosis of GCA [22].

SLE is an autoimmune inammatory disorder of the connective tissue and can involve multiple organs, including, among others, the skin, kid­ney, GI tract, brain, and vessel walls. Women are affected almost nine times more commonly than men [23]. If patients with SLE are screened, the eye is involved in 2–29% of patients with SLE [24].

Besides external eye involvement like kerato­conjunctivitis sicca, CWS are a vital clue to the presence of an active SLE and are seen in nearly 50% of patients with ocular involvement (Fig. 3.13) and often accompanied by retinal haemorrhages and vascular occlusions (Fig.3.14). Retinal vasculopathy is signicantly associated with neuropsychiatric SLE [25].